/* -*- Mode: c; tab-width: 8; indent-tabs-mode: 1; c-basic-offset: 8; -*- */

/*

 * Copyright (c) 1994, 1995, 1996, 1997, 1998

 *	The Regents of the University of California.  All rights reserved.

 *

 * Redistribution and use in source and binary forms, with or without

 * modification, are permitted provided that the following conditions

 * are met:

 * 1. Redistributions of source code must retain the above copyright

 *    notice, this list of conditions and the following disclaimer.

 * 2. Redistributions in binary form must reproduce the above copyright

 *    notice, this list of conditions and the following disclaimer in the

 *    documentation and/or other materials provided with the distribution.

 * 3. All advertising materials mentioning features or use of this software

 *    must display the following acknowledgement:

 *	This product includes software developed by the Computer Systems

 *	Engineering Group at Lawrence Berkeley Laboratory.

 * 4. Neither the name of the University nor of the Laboratory may be used

 *    to endorse or promote products derived from this software without

 *    specific prior written permission.

 *

 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND

 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE

 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE

 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE

 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL

 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS

 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)

 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT

 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY

 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF

 * SUCH DAMAGE.

 */

#ifdef HAVE_CONFIG_H

#include <config.h>

#endif

#include <sys/param.h>

#include <sys/ioctl.h>

#include <sys/socket.h>

#ifdef HAVE_SYS_SOCKIO_H

#include <sys/sockio.h>

#endif

#include <sys/time.h>				/* concession to AIX */

struct mbuf;		/* Squelch compiler warnings on some platforms for */

struct rtentry;		/* declarations in <net/if.h> */

#include <net/if.h>

#include <netinet/in.h>

#include <ctype.h>

#include <errno.h>

#include <memory.h>

#include <stdio.h>

#include <stdlib.h>

#include <string.h>

#include <unistd.h>

#ifdef HAVE_LIMITS_H

#include <limits.h>

#else

#define INT_MAX		2147483647

#endif

#include "pcap-int.h"

#ifdef HAVE_OS_PROTO_H

#include "os-proto.h"

#endif

/*

 * This is fun.

 *

 * In older BSD systems, socket addresses were fixed-length, and

 * "sizeof (struct sockaddr)" gave the size of the structure.

 * All addresses fit within a "struct sockaddr".

 *

 * In newer BSD systems, the socket address is variable-length, and

 * there's an "sa_len" field giving the length of the structure;

 * this allows socket addresses to be longer than 2 bytes of family

 * and 14 bytes of data.

 *

 * Some commercial UNIXes use the old BSD scheme, some use the RFC 2553

 * variant of the old BSD scheme (with "struct sockaddr_storage" rather

 * than "struct sockaddr"), and some use the new BSD scheme.

 *

 * Some versions of GNU libc use neither scheme, but has an "SA_LEN()"

 * macro that determines the size based on the address family.  Other

 * versions don't have "SA_LEN()" (as it was in drafts of RFC 2553

 * but not in the final version).

 *

 * We assume that a UNIX that doesn't have "getifaddrs()" and doesn't have

 * SIOCGLIFCONF, but has SIOCGIFCONF, uses "struct sockaddr" for the

 * address in an entry returned by SIOCGIFCONF.

 */

#ifndef SA_LEN

#ifdef HAVE_STRUCT_SOCKADDR_SA_LEN

#define SA_LEN(addr)	((addr)->sa_len)

#else /* HAVE_STRUCT_SOCKADDR_SA_LEN */

#define SA_LEN(addr)	(sizeof (struct sockaddr))

#endif /* HAVE_STRUCT_SOCKADDR_SA_LEN */

#endif /* SA_LEN */

/*

 * This is also fun.

 *

 * There is no ioctl that returns the amount of space required for all

 * the data that SIOCGIFCONF could return, and if a buffer is supplied

 * that's not large enough for all the data SIOCGIFCONF could return,

 * on at least some platforms it just returns the data that'd fit with

 * no indication that there wasn't enough room for all the data, much

 * less an indication of how much more room is required.

 *

 * The only way to ensure that we got all the data is to pass a buffer

 * large enough that the amount of space in the buffer *not* filled in

 * is greater than the largest possible entry.

 *

 * We assume that's "sizeof(ifreq.ifr_name)" plus 255, under the assumption

 * that no address is more than 255 bytes (on systems where the "sa_len"

 * field in a "struct sockaddr" is 1 byte, e.g. newer BSDs, that's the

 * case, and addresses are unlikely to be bigger than that in any case).

 */

#define MAX_SA_LEN	255

/*

 * Get a list of all interfaces that are up and that we can open.

 * Returns -1 on error, 0 otherwise.

 * The list, as returned through "alldevsp", may be null if no interfaces

 * were up and could be opened.

 *

 * This is the implementation used on platforms that have SIOCGIFCONF but

 * don't have any other mechanism for getting a list of interfaces.

 *

 * XXX - or platforms that have other, better mechanisms but for which

 * we don't yet have code to use that mechanism; I think there's a better

 * way on Linux, for example, but if that better way is "getifaddrs()",

 * we already have that.

 */

int

pcap_findalldevs_interfaces(pcap_if_list_t *devlistp, char *errbuf,

    int (*check_usable)(const char *), get_if_flags_func get_flags_func)

{

	register int fd;

	register struct ifreq *ifrp, *ifend, *ifnext;

	size_t n;

	struct ifconf ifc;

	char *buf = NULL;

	unsigned buf_size;

#if defined (HAVE_SOLARIS) || defined (HAVE_HPUX10_20_OR_LATER)

	char *p, *q;

#endif

	struct ifreq ifrflags, ifrnetmask, ifrbroadaddr, ifrdstaddr;

	struct sockaddr *netmask, *broadaddr, *dstaddr;

	size_t netmask_size, broadaddr_size, dstaddr_size;

	int ret = 0;

	/*

	 * Create a socket from which to fetch the list of interfaces.

	 */

	fd = socket(AF_INET, SOCK_DGRAM, 0);

	if (fd < 0) {

		pcap_fmt_errmsg_for_errno(errbuf, PCAP_ERRBUF_SIZE,

		    errno, "socket");

		return (-1);

	}

	/*

	 * Start with an 8K buffer, and keep growing the buffer until

	 * we have more than "sizeof(ifrp->ifr_name) + MAX_SA_LEN"

	 * bytes left over in the buffer or we fail to get the

	 * interface list for some reason other than EINVAL (which is

	 * presumed here to mean "buffer is too small").

	 */

	buf_size = 8192;

	for (;;) {

		/*

		 * Don't let the buffer size get bigger than INT_MAX.

		 */

		if (buf_size > INT_MAX) {

			(void)pcap_snprintf(errbuf, PCAP_ERRBUF_SIZE,

			    "interface information requires more than %u bytes",

			    INT_MAX);

			(void)close(fd);

			return (-1);

		}

		buf = malloc(buf_size);

		if (buf == NULL) {

			pcap_fmt_errmsg_for_errno(errbuf, PCAP_ERRBUF_SIZE,

			    errno, "malloc");

			(void)close(fd);

			return (-1);

		}

		ifc.ifc_len = buf_size;

		ifc.ifc_buf = buf;

		memset(buf, 0, buf_size);

		if (ioctl(fd, SIOCGIFCONF, (char *)&ifc) < 0

		    && errno != EINVAL) {

			pcap_fmt_errmsg_for_errno(errbuf, PCAP_ERRBUF_SIZE,

			    errno, "SIOCGIFCONF");

			(void)close(fd);

			free(buf);

			return (-1);

		}

		if (ifc.ifc_len < (int)buf_size &&

		    (buf_size - ifc.ifc_len) > sizeof(ifrp->ifr_name) + MAX_SA_LEN)

			break;

		free(buf);

		buf_size *= 2;

	}

	ifrp = (struct ifreq *)buf;

	ifend = (struct ifreq *)(buf + ifc.ifc_len);

	for (; ifrp < ifend; ifrp = ifnext) {

		/*

		 * XXX - what if this isn't an IPv4 address?  Can

		 * we still get the netmask, etc. with ioctls on

		 * an IPv4 socket?

		 *

		 * The answer is probably platform-dependent, and

		 * if the answer is "no" on more than one platform,

		 * the way you work around it is probably platform-

		 * dependent as well.

		 */

		n = SA_LEN(&ifrp->ifr_addr) + sizeof(ifrp->ifr_name);

		if (n < sizeof(*ifrp))

			ifnext = ifrp + 1;

		else

			ifnext = (struct ifreq *)((char *)ifrp + n);

		/*

		 * XXX - The 32-bit compatibility layer for Linux on IA-64

		 * is slightly broken. It correctly converts the structures

		 * to and from kernel land from 64 bit to 32 bit but

		 * doesn't update ifc.ifc_len, leaving it larger than the

		 * amount really used. This means we read off the end

		 * of the buffer and encounter an interface with an

		 * "empty" name. Since this is highly unlikely to ever

		 * occur in a valid case we can just finish looking for

		 * interfaces if we see an empty name.

		 */

		if (!(*ifrp->ifr_name))

			break;

		/*

		 * Skip entries that begin with "dummy".

		 * XXX - what are these?  Is this Linux-specific?

		 * Are there platforms on which we shouldn't do this?

		 */

		if (strncmp(ifrp->ifr_name, "dummy", 5) == 0)

			continue;

		/*

		 * Can we capture on this device?

		 */

		if (!(*check_usable)(ifrp->ifr_name)) {

			/*

			 * No.

			 */

			continue;

		}

		/*

		 * Get the flags for this interface.

		 */

		strncpy(ifrflags.ifr_name, ifrp->ifr_name,

		    sizeof(ifrflags.ifr_name));

		if (ioctl(fd, SIOCGIFFLAGS, (char *)&ifrflags) < 0) {

			if (errno == ENXIO)

				continue;

			pcap_fmt_errmsg_for_errno(errbuf, PCAP_ERRBUF_SIZE,

			    errno, "SIOCGIFFLAGS: %.*s",

			    (int)sizeof(ifrflags.ifr_name),

			    ifrflags.ifr_name);

			ret = -1;

			break;

		}

		/*

		 * Get the netmask for this address on this interface.

		 */

		strncpy(ifrnetmask.ifr_name, ifrp->ifr_name,

		    sizeof(ifrnetmask.ifr_name));

		memcpy(&ifrnetmask.ifr_addr, &ifrp->ifr_addr,

		    sizeof(ifrnetmask.ifr_addr));

		if (ioctl(fd, SIOCGIFNETMASK, (char *)&ifrnetmask) < 0) {

			if (errno == EADDRNOTAVAIL) {

				/*

				 * Not available.

				 */

				netmask = NULL;

				netmask_size = 0;

			} else {

				pcap_fmt_errmsg_for_errno(errbuf,

				    PCAP_ERRBUF_SIZE, errno,

				    "SIOCGIFNETMASK: %.*s",

				    (int)sizeof(ifrnetmask.ifr_name),

				    ifrnetmask.ifr_name);

				ret = -1;

				break;

			}

		} else {

			netmask = &ifrnetmask.ifr_addr;

			netmask_size = SA_LEN(netmask);

		}

		/*

		 * Get the broadcast address for this address on this

		 * interface (if any).

		 */

		if (ifrflags.ifr_flags & IFF_BROADCAST) {

			strncpy(ifrbroadaddr.ifr_name, ifrp->ifr_name,

			    sizeof(ifrbroadaddr.ifr_name));

			memcpy(&ifrbroadaddr.ifr_addr, &ifrp->ifr_addr,

			    sizeof(ifrbroadaddr.ifr_addr));

			if (ioctl(fd, SIOCGIFBRDADDR,

			    (char *)&ifrbroadaddr) < 0) {

				if (errno == EADDRNOTAVAIL) {

					/*

					 * Not available.

					 */

					broadaddr = NULL;

					broadaddr_size = 0;

				} else {

					pcap_fmt_errmsg_for_errno(errbuf,

					    PCAP_ERRBUF_SIZE, errno,

					    "SIOCGIFBRDADDR: %.*s",

					    (int)sizeof(ifrbroadaddr.ifr_name),

					    ifrbroadaddr.ifr_name);

					ret = -1;

					break;

				}

			} else {

				broadaddr = &ifrbroadaddr.ifr_broadaddr;

				broadaddr_size = SA_LEN(broadaddr);

			}

		} else {

			/*

			 * Not a broadcast interface, so no broadcast

			 * address.

			 */

			broadaddr = NULL;

			broadaddr_size = 0;

		}

		/*

		 * Get the destination address for this address on this

		 * interface (if any).

		 */

		if (ifrflags.ifr_flags & IFF_POINTOPOINT) {

			strncpy(ifrdstaddr.ifr_name, ifrp->ifr_name,

			    sizeof(ifrdstaddr.ifr_name));

			memcpy(&ifrdstaddr.ifr_addr, &ifrp->ifr_addr,

			    sizeof(ifrdstaddr.ifr_addr));

			if (ioctl(fd, SIOCGIFDSTADDR,

			    (char *)&ifrdstaddr) < 0) {

				if (errno == EADDRNOTAVAIL) {

					/*

					 * Not available.

					 */

					dstaddr = NULL;

					dstaddr_size = 0;

				} else {

					pcap_fmt_errmsg_for_errno(errbuf,

					    PCAP_ERRBUF_SIZE, errno,

					    "SIOCGIFDSTADDR: %.*s",

					    (int)sizeof(ifrdstaddr.ifr_name),

					    ifrdstaddr.ifr_name);

					ret = -1;

					break;

				}

			} else {

				dstaddr = &ifrdstaddr.ifr_dstaddr;

				dstaddr_size = SA_LEN(dstaddr);

			}

		} else {

			/*

			 * Not a point-to-point interface, so no destination

			 * address.

			 */

			dstaddr = NULL;

			dstaddr_size = 0;

		}

#if defined (HAVE_SOLARIS) || defined (HAVE_HPUX10_20_OR_LATER)

		/*

		 * If this entry has a colon followed by a number at

		 * the end, it's a logical interface.  Those are just

		 * the way you assign multiple IP addresses to a real

		 * interface, so an entry for a logical interface should

		 * be treated like the entry for the real interface;

		 * we do that by stripping off the ":" and the number.

		 */

		p = strchr(ifrp->ifr_name, ':');

		if (p != NULL) {

			/*

			 * We have a ":"; is it followed by a number?

			 */

			q = p + 1;

			while (isdigit((unsigned char)*q))

				q++;

			if (*q == '\0') {

				/*

				 * All digits after the ":" until the end.

				 * Strip off the ":" and everything after

				 * it.

				 */

				*p = '\0';

			}

		}

#endif

		/*

		 * Add information for this address to the list.

		 */

		if (add_addr_to_if(devlistp, ifrp->ifr_name,

		    ifrflags.ifr_flags, get_flags_func,

		    &ifrp->ifr_addr, SA_LEN(&ifrp->ifr_addr),

		    netmask, netmask_size, broadaddr, broadaddr_size,

		    dstaddr, dstaddr_size, errbuf) < 0) {

			ret = -1;

			break;

		}

	}

	free(buf);

	(void)close(fd);

	return (ret);

}